First advice: enlist a friend. Much of the detail is going to depend on the packing, and how the box/crate opens. For my 150lb/55 inch towers, the best method was to stand boxes upright, open on a long side and "walk" the speaker out, with gentle pulls on alternate sides. On hard floors, blanket on the floor will help with sliding speaker into approximate position before engaging the spikes/footers. Goes without saying, but the floor should be absolutely clean to avoid predations of scratchy grit.
Perhaps the manufacturer has some advice?
John